JULY, 1900. GRAENICHER— FERTILIZATION OF SYMPHORICARPOS, ETC. 141 
The Fertilizotion of Symphoricarpos and Lonicera* 
By Dn S. GRAENICHER. 
Symphoricarpos and Lonicera are two closely related genera, 
belonging to the Caprifoliaceae or honeysuckle-family. In our 
flora these two genera, taken together, are represented by 7 
species of plants, all of which occur in the immediate vicinity 
of the city of Milwaukee. 
Symphoricarpos, Juss. 
One of our species, Symphoricarpos racemosns, Michx., has 
been enumerated among the so called 'Vasp-flowers" ever since 
H. Mueller (i) in giving an account of the fertilization of this 
species, mentioned the fact that wasps are among the principal 
visitors of the flowers. His observations were made on plants 
of this species, growing at different points in Germany, and fur- 
nished the remarkable results that in a certain part of that 
country, with an abundance of wasps, the latter formed over nine 
tenths of the visitors, while in an other locality, where wasps 
seemed to be scarce, bees were the most frequent visitors. More 
recent investigators have obtained similar results, as for example 
Knuth (2), who for years never succeeded in witnessing the visit 
of a single wasp on Symphoricarpos racemosus in Pommerania, 
until in 1897, when wasps, belonging to several species were 
numerous on these flowers in Usedom, an island on the coast 
of Pommerania. This is significant, and shows that the extent 
tQ which these flowers receive the attention of wasps in a given 
locality, depends mainly on the frequency, with which wasps 
occur in that locality. Where wasps are few in number, the flow- 
ers are visited efficiently by a variety of other insects, mostly 
bees and flies, and according to MacLeod's (3) observations in 
Flanders by moths (Noctuidae). For this reason there has been 
a tendency on the part of a few observers to drop the term 
"wasp-flower", the visits of wasps to such a flower being, in their 
opinion of no more importance than the visits of wasps to any 
other flower. But the fact must be admitted that a wasp-flower 
is more attractive to wasps, than is the ordinary beeflower. The 
dimensions of such a flower, together with its bellshaped or cup- 
shaped form, enable wasps to thrust their heads into the flower 
(1) H. Mueller. Die Befruchtung: der Biumen durch Inseckten, 1873. pp. 360-361. 
(2) P. Knuth. Handbuch der Bluetenbiologie, 1898. Vol. ll, Part 1, p. 527. 
(3) MacLeod. Untersuchungen ueber die Befruchtung der Biumen. Bot. Centralblatt. Vol. 
XXIX, p. 119, 1887. 
